[#719] Add Job.afterRequest() to schedule job after request is served

TIcket: http://play.lighthouseapp.com/projects/57987/tickets/719-starting-a-job-now-that-references-a-newly-created-entity-doesnt-work

I implemented something like John suggesterd. Instead of later method for scheduling job is called: afterRequest. 
If called not from http invocation, it works just like .now();